range lead units of pressure gauge

[LRP]

i,ve been reading up on c.u.p and l.u.p.
the lead units of pressure is used for lower pressure.
it would be nice if somebody would develop a range
system to check the pressure in our antique guns.
i can see useing a special pair of adjustable pliers for diff size brass that would put a little dimple in the brass.
u would stick a thin disc or strip of lead in the brass dimple,
load and fire. u would use a lee type of microscope that they use for the lead hardness tesster. it has a calbrated scale
that would tell u how much wider it got . u would then look at a chart which tell u the pressure. i know, i get these brain farts
ever so often. if i was rich, i would buy the OEHLER chrono
with the pressure transducer.
cheers

 

[DWalt]

The use of LUP and CUP for chamber pressure measurement is a holdover from the days when electronics did not exist. At best, they are imprecise and do not actually measure peak chamber pressure, but rather are simply analogous the area under the pressure-time curve. While the CUP and LUP methods are still covered under SAAMI pressure measurement standards, you are absolutely wasting your time in even considering them for home use, for any of many very good reasons. Forget it. The idea you propose could not and would not work.

Virtually all industry and government chamber pressure testing worldwide now uses some type of system based upon a very rapid response piezoelectric pressure gauge that allows an actual pressure vs. time trace to be captured and is capable of very precisely determining the actual peak chamber pressure. These systems are quite expensive, complicated, and are therefore wholly unsuitable for use by individuals. Piezo-based systems (and there are several types) are vastly superior to the old CUP and LUP methods for those users that actually need this data every day.

For both of the previous methods, a specially-designed or modified dedicated pressure gun is required. Not likely that many could afford those also, or would even be able to use one.

There is a system sold for use by individual reloaders that is reported to be almost as good as a piezo gauge. It uses an external strain gauge which is cemented to the exterior of the barrel of an ordinary rifle or shotgun. It is a bit costly, but is within the financial reach of many. Having not used it myself, I can offer no opinion, but there's quite a bit of information on the internet about it. If you want to use such a strain gauge system for pistol ammunition, you would necessarily have to use something like a single shot Thompson Center handgun caliber barrel chambered for the caliber you desire. YOU CANNOT USE YOUR ANTIQUE HANDGUNS FOR THIS PURPOSE!!!

 

[LRP]

well DWalt; you are correct except the part about wasteing my
time. the avarage reloader has nothing but a chrono to
go by to load for these antiques. the lyman reloader 46th
edition has the vel and pressure for the 38 spl. that is going to be my test bed. i have built 4 airoplanes and logged 5000 hrs
on them and no problems. now i know how the wright bros
felt. that thig will not fly. LOL. it,s not going to cost much to try.
never say die.
cheers